1. Field of the Invention
The present invention relates to a vacuum processing method for transporting and treating an object in a vacuum atmosphere.
2. Description of the Related Art
In manufacturing a semiconductor wafer (hereinafter referred to as a wafer), various treatments are performed in a vacuum atmosphere. For example, a treatment of implanting an impurity into an object, i.e., a wafer, is performed by an ion implantation apparatus. This treatment is performed in the following manner: a wafer is extracted from a cassette in a process chamber maintained in a vacuum atmosphere by a handling device and disposed on a disk-like treatment table; and the treatment table is turned and slid, so that the entire surface of the wafer is scanned and uniformly irradiated with ion beams. In this treatment, to prevent the wafer from being charged and adhering to the treatment table, exciting species including ions generated by, for example, a plasma generating section in the process chamber, are irradiated on the wafer as an electron shower, thereby neutralizing the charge on the wafer. When this treatment is completed, the wafer on the treatment table is returned to the cassette by the handling device, and the cassette is transported to a next treatment section.
Since the wafer in treatment is subjected to the antistatic treatment as described above, it is prevented from adhering to the treatment table. However, after the treatment, in a case where the wafer is transported by the handling device, a high potential of several hundreds volts may be generated at a time when the wafer is removed from the treatment table. Owing to the high potential, the wafer is charged and adheres to the handling device. If the handling device, to which the wafer adheres, transports another wafer to or from the cassette, the wafers may be damaged and the wafer transportation may be hindered. Further, various problems, such as adhesion of particles to the charged wafer, may arise.